I almost forgot to comment on the AM-21. I was orginally told by DirecTV that it would be an add-on off-air tuner for both the HD DVR units (hr-21, hr-23, hr-whatever) AND the HD non-DVR units (h-21, h-22, h-23, etc). The latest I have heard is that they intend for them to be added on (via the USB port on the back of the receiver) ONLY to the DVR units. To make matters worse, the DVR units don't work that well in a motorhome. They are very "finicky" about wanting to see both satellite inputs, and to be locked onto all the satellites all the time. Setup is a nightmare to get right as well. Good luck if you chose to install one on a single satellite in-motion dish. God help you if you have both the Slimline 5 and an inmotion dish, intending to go back and forth with the DVR. You'll have to go back through the setup 20-minute ordeal each time you switch to get all the channels. Sorry for the news, but I have to be honest. Good luck.